2008projectindex060Cannada

Medical Student Research Fellowship for Summer 2008

Mentor: Lisa K. Cannada MD
Department: Orthopaedic Surgery
Room number: G.840
Mail Code: 8870
Phone number: 214-648-8768
E-mail:lisa.cannada@utsouthwestern.edu

Project 1

Project title: Early Weight Bearing With Small Fragment Hybrid Locking Dcp: A Biomechanical Study And Case Series

Human subjects IRB approved project number (where applicable): #012008-075
Animal subjects IRB approved project number (where applicable):

Brief Description of Project:

Closed non-operative treatment of humeral shaft fractures remains the standard of care in many instances, with very good results.1-4. However, there are many indications for the operative stabilization of these fractures, including obesity, multiple injuries, bilateral injuries, and associated vascular or neurological injuries3, 5-11. In many instances, the indication is to facilitate comfort, nursing care, and mobilization. However, most authors recommend a gentle rehabilitation program which includes non-weight bearing ROM exercises early, and resumption some weight bearing at 6 weeks, with full weight bearing only at radiographic union12-13. However, one series did compare patients who were allowed to weight bear immediately because of lower extremity injuries and those who were rehabilitated in the conventional fashion, showing no difference in failure rates14 .
In addition, the traditional recommendation for implant selection is the use of a 4.5 mm wide LCDCP12-13 . However, recent advances in plate technology, with the advent of locked and hybrid designs, has brought about new information on the relative strength of various constructs. Clearly, locked and hybrid constructs are much stronger than traditional compression plates15-18.
Available information leaves some unanswered questions: what is the relative strength of the traditional 4.5 mm plates and smaller 3.5 mm plates given locked and hybrid screw placement? There are several patients whose bone is quite small to accept the larger 4.5 mm locking plate. In addition, the known increased stiffness of locked plating has lead to some clinicians to use smaller 3.5 mm combination plates for humerus fractures. The answers to the biomechanical testing may provide useful data for clinical application. The lead author has a three year series of several patients treated with the 3.5 mm hybrid technique who were permitted weight bearing due to their lower extremity injuries. using hybrid technique. We will evaluate those results, and in conjunction with our biomechanical study, will answer the question is early weight bearing of humerus fractures in the multiple trauma patient safe with hybrid techniques. The last study on this was prior to the advent of locked plates and used large fragment plates.14
STUDY OBJECTIVES:
1. To demonstrate the biomechanical properties of small and large fragment locking plates used in locking mode and hybrid mode.
2. To report a clinical series of humerus fractures treated with small fragment LCP in hybrid mode, with immediate weight bearing.

References
1. Sarmiento A, Kinman PB, Galvin EG, et al. Functional bracing of fractures of the shaft of the humerus. J Bone Joint Surg Am 1977;59:596-601.
2. Balfour GW, Mooney V, Ashby ME. Diaphyseal fractures of the humerus treated with a ready-made fracture brace. J Bone Joint Surg Am 1982;64:11-13
3. Zagorski JB, Latta LL, Zych GA, et al. Diaphyseal fractures of the humerus: treatment with prefabricated braces. J Bone Joint Surg Am 1988;70:607-610.
4. Foulk DA, Szabo RM. Diaphyseal humerus fractures: natural history and occurrence of nonunion. Orthopedics 1995;18:333-335.
5. Bell MJ, Beauchamp CG, Kellam JK, et al. The results of plating humeral shaft fractures in patients with multiple injuries: the SunnyÍbrook experience. J Bone Joint Surg Br 1985;67:293-296.
6. Bleeker WA, Nijsten MW, ten Duis HJ. Treatment of humeral shaft fractures related to associated injuries: a retrospective study of 237 patients. Acta Orthop Scand 1991;62:148-153
7. Brumback RJ, Bosse MJ, Poka A, et al. Intramedullary stabilization of humeral shaft fractures in patients with multiple trauma. J Bone Joint Surg Am 1986;68:960-970.
8. Vander Griend R, Tomasin J, Ward EF. Open reduction and internal fixation of humeral shaft fractures: results using AO plating techniques. J Bone Joint Surg Am 1986;68A:430-433.
9. Foster RJ, Dixon GL Jr, Bach AW, et al. Internal fixation of fractures and non-unions of the humeral shaft: indications and results in a multi-center study. J Bone Joint Surg Am 1985;67:857-864.
10. Foster RJ, Swiontkowski MF, Bach AW, et al. Radial nerve palsy caused by open humeral shaft fractures. J Hand Surg [Am] 1993;18:121-124.
11. Gainor BJ, Metzler M. Humeral shaft fracture with brachial artery injury. Clin Orthop 1986;204:154-161.
12.Wiss, DA ed. Master Techniques in Orthopaedic Surgery: Fractures. Lipincott Williams and Wilkins. Philadelphia, PA: 2006.
13. Browner, BD, Jupiter JB et al eds. Skeletal Trauma. Saunders, Philafelphia, PA> 2003.
14. Tingstad EM, Wolinsky PR, Shyr Y, Johnson KD. Effect of immediate weightbearing on plated fractures of the humeral shaft. J Trauma. 2000 Aug; 49(2):278-80.

15. Gardner MJ, Griffith MH, Demetrakopoulos D, et al. Hybrid locked plating of osteoporotic fractures of the humerus. JBJS. 2006: 88(9):1962-7.

16. Gardner MJ, Brophy R, Campbell D et al., et al. The Mechanical Behavior of Locked Compression Plates compared with Dynamic Compression Plates in Cadaver Radius Model. JOT. 19(9) Oct 2005. 597-603.

17. Ahmad M, Nanda R, Bajwa AS, Candal-Couto J, Green S, Hui AC. Biomechanical testing of the locking compression plate: when does the distance between bone and implant significantly reduce construct stability? Injury 2007 Mar; 38 (3): 358-64.

18. Sanders R, Haidukewych G, Milne, T, et al. Minimal vs Maximal plate fixation techniques of the ulna: The biomechanical effects of number of screws and plate length.
JOT. 2002. 16 (3) p. 166-171.

Project 2
Project title: Fetal Outcomes in Orthopaedic Trauma Patients

Human subjects IRB approved project number (where applicable): 062006-027

(This is same IRB as Childbirth After Pelvic Fractures-we are looking at those patients who were pregnant at the time of their trauma)

Animal subjects IRB approved project number (where applicable):

Project Type (patient-based research, animal-based research, or basic research; this characterization is only to permit a general classification for grouping similar types of projects) Patient Based. The medical student will collect data on the pregnant trauma patients with orthopaedic injuries and the fetal outcomes.
Project 2
Project Summary: Fetal Outcomes in Orthopaedic Trauma Patients
PURPOSE: To determine the effect of orthopaedic trauma on fetal outcomes in pregnant trauma patients
BACKGROUND: Trauma in pregnancy is a major cause of morbidity and mortality for both mother and fetus1-4. It is leading non-obstetrical cause of maternal death in pregnancy, accounting for more than 1 million maternal deaths each year worldwide5-8. Because of a lack of standardized reporting mechanisms for the sequelae of maternal trauma to the mother and fetus, many authors believe that it is an underreported problem6,7,10.
More recently, there have been reports of not only immediate maternal and fetal outcomes of trauma, but longer term sequelae to the fetus. 4,9. In one study, fractures, dislocations, sprains, and strains were the most common type of injury. In women who sustained prenatal trauma sustained also resulted in increased risks at delivery: placental abruption OR 1.6 (95% CI 1.3-1.9), preterm labor OR 2.7 (95% CI 2.5-2.9), maternal death OR 4.4 (95% CI 1.4-14) 4. In a recent report from our center demonstrated that mothers that suffer a trauma with an injury have a higher risk pre-term delivery and of birth weight infant than those who sustained a trauma mechanism with an ISS of 09.
A large proportion of trauma patients, specifically those with low ISS scores, are treated at non level 1 trauma centers. In this setting, a pregnant patient may be referred primarily to an orthopaedist for follow up of injuries. The risk of these patients for poor long term fetal outcomes is important information for the orthopaedic community11.
CONCISE SUMMARY OF PROJECT: This project will provide a summary of the immediate maternal and fetal outcomes of the pregnant trauma patient with orthopaedic injuries. In addition, it will provide a summary of long term fetal outcomes in those patients discharged home with a viable fetus.
CRITERIA FOR INCLUSION OF SUBJECTS: All patients available through the Parkland Memorial Hospital trauma registry database with a medical co morbidity code of P.00 (pregnancy) will be included
CRITERIA FOR EXCLUSION OF SUBJECTS:
1. The immediate outcomes for mother and fetus will be reported for all patients
2. In the long term fetal outcome analysis, some patients will be excluded:
a. Patients who do not give birth at our institution
b. Patients with incomplete data
c. Twin births (higher risk)
SOURCES OF RESEARCH MATERIAL: There will be two sources of data:
1. The Parkland Memorial Hospital trauma registry database
2. The Parkland Memorial Hospital Obstetrical Database

RECRUITMENT OF SUBJECTS: There will be no recruitment of subjects for this retrospective database study.
POTENTIAL RISKS: There will be no potential risks to subjects for this retrospective database study.
SPECIAL PRECAUTIONS: There will be no special precautions necessary for this retrospective database study.
PROCEDURES TO MAINTAIN CONFIDENTIALITY: The only identifying data that is required for this study is the medical record number, which will be used to merge the two databases.
This identifying data will be available only to the authors, and statisticians, involved in this study. All information will be kept in a password protected computer.
POTENTIAL BENEFITS: The benefits of this study are in the educational value of the results. Information on the expected outcomes of pregnant orthopaedic trauma patients will provide guidance to the orthopaedist for when to refer to an obstetrician. In addition, this information will be useful in planning preventative strategies.
BIOSTATISTICS: The primary outcomes (LBW and PTD) in pregnant trauma patients will be answered as follows: The total number of patients discharged with a viable fetus who returned for delivery will be evaluated (based on previous studies, N likely to be 900). Of those patients, those with an orthopaedic injury will be included in the injured group, and compared to a non-injured group. Those with either a PTD or LBW will be considered to have a complication.
The comparison will be carried out as follows:
1. Incidence of complication in orthopaedic injured patients and non-injured patients: Fishers exact test or chi-squared test.
2. A comparison between groups for patient and trauma factors, to evaluate the two groups
3. Creation of a regression model to include known risk factors for complication and trauma related factors, in order to delineate the OR for each factor :
a. Maternal age
b. Smoking
c. Race
d. Nulliparity
e. BMI
f. ISS
g. Trauma mechanism
h. Presence of abdominal injury
i. Early vs late GA (< 24 hours)
j. SBP in ER
RISK/BENEFIT ASSESSMENT: In this retrospective review, there is minimal risk and significant benefit.
References
1. Fildes J, Reed L, Jines N, et al. Trauma, the leading cause of maternal death. J Trauma. 1992; 32: 643-5.
2. Patterson RM. Trauma in pregnancy. Clin Obstet Gynecol. 1984; 27: 32-8.
3. Peckham CH, King RW. A study of intercurrent conditions observed during pregnancy. Am J Obstet Gynecol. 1963; 87: 609-24.
4. El Kady D, Gilbert WM, Anderson J wt al. Trauma during pregnancy: an analysis of maternal and fetal outcomes in a large population. AJOG. 2004; 190: 1661-1668.
5. Kissinger DP. Rozycki GS, Morris JA Jr, et al. Trauma in pregnancy. Predicting Pregnancy Outcome. Arch Surg 1991; 126: 1079-86.
6. Weiss HB, Songer TJ. Fabio A. Fetal deaths reated to maternal injury. JAMA 2001; 286: 1863-8.
7. Weiss HB, Lawrence B, Miller T. Prevalence and risk of hospitalized pregnant occupants in car crashes. Anni Proc Assoc Adv Automot Med. 2002; 46: 336-355.
8. American College of Obstetrics and Gynecology, Motor vehicle Crashes during Pregnancy, ACOG educational Bulletin No. 251, 1998.
9. Speery JL, Casey BM, McIntyre DD et al. Long-term fetal outcomes in pregnant trauma patients. Am J Surg. 2006; 192: 715-21.
10. El Kady D. Perinatal Outcomes of Traumatic Injuries During Pregnancy. Clin Obstet and Gynecol. 2007; 50 (3), 582-91.
11. MacKenzie EJ, Hoyt DB, Sacra JC et al. National Inventory of Hospital Trauma Centers. JAMA. 2003; 289 (12): 1515-1522.